1. Field of the Invention
The present invention relates to an optical functioning component provided in an optical connector comprising an optical connector-adaptor and an optical connector-plug for carrying out a predetermined amount of attenuation.
2. Description of the Related Art
There has been used conventionally an optical functioning component having a mechanism for attenuating, cutting off, reflecting or absorbing light by means of a fiber or a filter, which can attenuate light or cut off, reflect or absorb a specific wavelength of light, such as an optical attenuator for carrying out a predetermined amount of light-attenuation by means of a metal-doped attenuation fiber or an attenuation filter formed by an optical absorber, the optical attenuator being provided in an optical connector comprising an optical connector-adaptor and an optical connector-plug.
Such optical functioning component has one end formed in a shape roughly equal to an optical connector-plug so as to engage with a connecting portion to which the optical connector-plug of an optical connector-adaptor is connected and the other end formed in a shape equal to a connecting portion of the optical connector-adaptor so that a front end of the optical connector-plug can be connected.
Such example is shown in FIG. 7. FIG. 7 is a perspective view of an optical functioning component in accordance with a related art.
As shown in FIG. 7, a conventional optical functioning component 210 is an optical functioning component used for an MU-type optical connector and comprises a ferrule 220 having an attenuation mechanism or a mechanism for cutting off, reflecting or absorbing a specific wavelength of light, an optical connection sleeve for holding an end of the ferrule 220, the optical connection sleeve being not shown in the drawing, a frame 240 for holding the optical connection sleeve and a housing 250 for holding the frame 240 inside so that the frame 240 can move axially and freely by a predetermined amount.
An insert portion 251 to be inserted and held in an MU-type optical connector-adaptor is provided on the front end side of the housing 250 and the frame 240. On the rear end side, there is provided a plug holding portion 252 in which an MU-TYPE optical connector-plug is inserted and held.
The insert portion 251 is formed in a shape equal to the MU-type optical connector-plug, while the plug holding portion 252 is formed in a shape equal to a connecting portion of the MU-type optical connector-adaptor.
The ferrule 220 of an optical connector-plug inserted and held in the plug holding portion 252 of the housing 250 is adapted to contact with another ferrule 220, which has an attenuation mechanism or a mechanism for cutting off, reflecting or absorbing a specific wavelength of light in the optical connection sleeve, at respective end surfaces to be opposingly connected each other.
In such an optical functioning component 210, holding an optical connector-plug in the plug holding portion 252 and inserting and holding the insert portion 251 in a connecting portion of an optical connector adaptor allow optical connection of a pair of optical connector-plugs connected opposingly in an optical connector-adaptor to be attenuated by a predetermined amount.
The above-described conventional optical functioning component, however, has a problem that, in an optical connector-adaptor capable of optical-connection while a plurality of optical connector-adaptors such as two or eight, for example, are provided in parallel, inserting and holding the optical functioning component in respective connecting portions of an optical connector-adaptor requires a predetermined space to be provided between adjoining connecting portions of the optical connector-adaptors so that respective plug holding portion sides of adjoining optical functioning components would not contact each other, which causes the optical connector-adaptor not to be miniaturized.
Furthermore, an optical connector-adaptor for holding a plurality of optical connector-plugs provided in parallel without using any optical functioning component should be formed separately from an optical connector-adaptor using an optical functioning component, which causes a cost to be high.
In the case that an adaptor holding portion of a housing of an optical functioning component is thinly formed so that a space between connecting portions of an optical connector adaptor would be small, especially in an optical functioning component for a small size optical connector such as an MU-type optical connector, a strength of the adaptor holding portion cannot be maintained, so that the adaptor holding portion would be easily broken.
Moreover, in the conventional optical functioning component, it is necessary to provide outside an adapter a rear end having a larger size than the cross-sectional area of a plug in order to insert and hold an optical connector-plug, which makes the whole length of the optical functioning component long, so that a ferrule having an optical function should be made long. The ferrule length of a conventional MU-type optically fixed attenuator, for example, is 16 mm or more, so that many expensive attenuation fibers should be used, which causes a cost to be high.